DESCRIPTION (provided by investigator): The directed beating of motile cilia is a critical aspect of tissue function in a variety of developmental and physiological contexts including proper neural development, egg migration through the oviduct and mucus clearance in the respiratory tract. The loss of cilia motility results in a wide range of phenotypes including hydrocephaly, infertility, situs inversus, and respiratory dysfunction. We have developed the ciliated epithelium of Xenopus larval skin as a model system to ask: How do ciliated cells generate hundreds of cilia and how do they orient those cilia in an organized way? We have developed confocal light microscopic methods for visualizing specific aspects of ciliated cells in the developing skin of Xenopus embryos. These methods allow us to visualize the massive centriole duplication required to generate the approximately 100 basal bodies that nucleate the cilia. Additionally, we can visualize and accurately quantify the developmental process by which cilia orientation goes from weakly biased to precisely oriented, a process we call cilia refinement. Using these methods we will address: (1.) The dynamics of cilia refinement, (2.) The regulation of cilia refinement, and (3.) The regulation of centriole duplication. Our results will provide useful information regarding the development of ciliated epithelia. Additionally, loss of cilia and ciliated cells, followed by regrowth, occurs in mature ciliated epithelia in response to transient events including chemical insult (e.g. smoke inhalation), natural processes (e.g. menstrual cycle), and disease (e.g. asthma). Results from our experiments will provide a model for understanding the homeostasis of ciliated cell polarity that is relevant for designing novel therapies directed towards accelerating the rate of cilia reorientation after respiratory stress.